antonoff



G. N. ANTONOFF.

ELECTRIC BATTERY.

APPLlcAnoN FILED Aue. l2. ma.

1,303,844. Patented May 20, 1919.

2 SHEETS-SHEET l.

G. N. ANTONOFF.

ELECTRIC BATTERY.

APPLlcmoN msn Amma. 191s.

1,303,844. Patented May 20, 1919.

2 SHEETS-SHEET 2.

Mmmm m' 21,75%?? Mmmm' y GEORGE NIKOLAYEVICE AN TON OFF, OF LONDON,ENGLAND.

ELECTRIC BATTERY.

Specification of Letters Patent. Patented May 20, 1919.

Application med August 12. 191s. semi No.l 249,553.

To all 'whom t may concern.'

Be it known that I, GEORGE l\T1xo1.Arrzv1oHl AN'roNorF, a subject ofRussia, and residing at yIndia House, Kingsway, London, W. C. 2,England, have invented certain new and useful Improvements Relating toElectric Batteries, of which the following is a specification.

This invention relates to electric batteries and especially to primarycells, whether in the wet or so 'called dry for-m, in whichv zinc isused as a source of energy and carbon is used for the negative pole withmanganese di-oxid as the depolarizer.

The carbon electrode has usually in close contact with it a mixtureconsisting of finely divided manganese di-oxid and nely dividedgraph-ite,.with or without an agglutinant molded or pressed togetherunder a heavy pressure, and it has hitherto been believed that betterresults were obtained the higher the pressure employed.

Now I have found by experiment that there is a critical point-1n therelation between the internal resistance of the cell and the pressure towhich the mixture of manganese di-oxid and carbon has been sub]ect Asthe pressure to which the mixture has been submitted is increased fromzero the internal resistance is found to diminish up to a point andafter that is passed to increase steadily.

Further, in the ordinary Leclanch cell on closed circuit through anexternal resistance of, say 10 ohms, for example, the characteristic ofthe current curve lotted to a time base is that it rapidly falls omthe'beginning, has a short approximately horizontal part about theregion of 0.8 ofiia volt, and then falls away rapidly again, becoming ina short time practically useless.

Now I have found that when the depolarizer mixture has been pressed toabout the point which gives the least internal reslstance the horizontalpart of the curve is very greatly extended and the useful life of thecell becomes correspondingly greater. Such cells in which thedepolarizer mixture has been compressed to aboutthe point givingtheleast internal reslstance form the subject-matter of my co-pendingBritish application No. 11081 of 1917. e

The object of the present inventlon 1s to improve the output of suchcells.

or electromotive force- Now the cause of the rapid falling olf ofcurrent on closed circuit is due in part to the which lowers thepotential, `and in lpart to the formation of insoluble salts in thecapillaries of the depolarizer mass which increases the internalresistance. I have found that the output of the above described Leclanchtype cells can be su'bstantially improved by the addition of bodiesfulfilling the following requirements (a) They must have little or noaction on manganese di-oxid. i

(b) They must have little or no action on zinc in the usual batterysolution; and

(c) Their ammonia and zinc salts must be freely soluble in the'batterysolutions.

Suitable bodies will bel found, for example, among the weak organicacids such,

`setting free of ammonia at the negative pole,

for example, as benzoic acid, tartaric acid,

salicylic acid, or succinic acid or their homologues. function. They actat the early p-art of the life of the battery (while re-acting with theammonia which tends to be set free at the negative pole) toprevent thelowering of the potential So rapidly as would otherwise take place.Agtain during the later part of the life of the attery after the firstrapid fall of otential thebodies' produced in the cell by t e reactiontend to give a characteristic diminishing with time to the internalresistance of the cell. This is in contrast to the rising resistancecharacteristic of cells of ordinary construction.

I am aware that it has before been proposed to add acetic acid and otherorganic acids to ordinary Leclanch type cells, but the present inventiondoes not relate to such ordinary cells, but-'only to those of the newtyple above indicated.

, he invention consists in employing in electric cells in which thedepolarizer mixture has been pressed to about the critical Suchbodies'4A perform av two-fold ressure bodies fulfilling the requirementsi They invention also consists in the improved Leclanc'h type cellshereinafter de" scribed.

l `igure 1 shows the Icurve obtained by plotting the internalresistances of a series of cells (determined by the Wheatstone The curveA-B is typical of that from anl ordinaryl Leclanch cell, and the curveA-C is typical of that from a cell according to the present invention.kThese discharge curves are obtained by discharge through an externalresistance of 10 ohms with a cell of mm. square by 125 mm. long.

Fig. 3 illustrates' diagrammatically one form of cell according to thisinvention, in whi'ch'a' is a zinc cylinder sutliciently thick not to bedeformed by any pressure developing during working.- The bottom 4Z2 isconveniently formed of a dished disk, autogenously welded to thecylinder. c isthe usual absorbent layer employed inside the cylinder topermit only of electrolytic conduction between the zinc and the carbonpoles. d is the depolarizer mass, and e is the canbon electrode; f is alayer of paper on the top of the depolarizer mass; g is a zinc coverplate with upwardly projecting Hange and a hole somewhat larger than thediameter of lthe carbon, to permit of the insertion of a centralizingring of cardboard it. z' is another paper Washer placed on the top ofthe zinc disk and cardboard ring. c is a layer of husks to absorb anyliquid which may exude from the cell. Z is a layer of pitch sealing inthe husks in position;

f through the pitch and bitumen.

and m is a further paper disk separating the pitch and the husks. n is alayer of bitumen on the rtop of lthe pitch, and o is a vent l The zinccap or disk g is autogenously welded in place in the zinc cylinder andis stili? enough to prevent any longitudinal expansion of thedepolarizerma during the life of the cell. j? 1s a carbon terminal, and g aterminal on the zinc cylinder.

In carrying this invention into effect in one form as applied toLeclanch type Acells in which the negative pole is prepared according tomy (3o-pendingy British application No. 11081 of 1917, I prepare themixture of manganese dioxid an'd graphite, about 40% graphite and 60%manganese dioxid, and I add a small proportion, say about 1% of benzoicacid in a finely divided state. I then make urp the mixture into a pastewith distilled Water and fill it in around the carbon plate into amolding cylinder. Pressure is then applied by means of suitable 'moldingblocks in a screw or hydraulic press, and the predetermined pressurethus put upon the depolarizer mass. l

It is found that with all the ordinary va.- rieties of the components ofthe mixture `there is a critical region of pressure within which theinternal resistance attains a minimum value. The absolute value of thiscritical pressure, however, varies with the actual materials used,namely, with the quality and state of division of the graphite and themanganese dioxid. It is therefore necessary to determine for every givenbatch of materials what the critical pressure is. This may be donereadily by an actual experiment, making a nulmber of cells withdifferent pressures and plotting the internal resistance against thedifferent pressures.

When the depolarizer has been molded around the plate under the criticalpressure as above described, it is removed from the press and the moldedlblock is forced out of the mold. It will be found that its surface islstill slightly plas-tic, so that it can be slightly deformed with 'thelingers. rlhe critical pressure may vary from about 20 lbs. to about 7 0lbs. per square inch.

The negative pole thus prepared is placed in a zinc container with theusual solution soaked lining and the cell completed in the usual way,care being taken that the container is a good enough t, and strongenough to retain the pressure. r

The presence 0f the additional body, benzoicv acid` in this case, tendsto prevent the formation of insoluble salts which are azpt to clog upthe capillaries of the depolarizer, and thus tends to keep *the internalresist` ance low, and it also prevents the carbonic acid of the airacting deleteriously upon the cell. In one instance, for example, I havefound that the cell prepared in the way ind lcated albove and tested onan external resistance of 5 ohms had only fallen to .92 of a volt aftereleven days working, and the internal resistance had fallen 40% belowits initial value.

Having now described my invention what I claim as new and desire tosecure by Letters Patent is 1. An electric cell having its depolarizermolded under about the critical pressure giving minimum internalresistance and containing a small proportion of one or more weak organicacids.

2. An electric cell having a depolarizer mixture subjected to a pressurein the region of the critical pressure giving an internal resistance tothe cell about a minimum value land containing a small proportion of aweak mixture subjected to a pressure in the region of the criticalpressure giving an lnternal resistance to the cell about a minimum valueand containing a small proportion of. a plu-v rality of weak prganicacid. i v

4. An electrlc cell havmg. a depolarlzer mixture subjected to a pressurein the region of the critical pressure giving an internal resistance tothe cell about a minimum valuel and containing a small proportion ofzoic acid.

5. 'A ,dry cell of the Leclanch type havin its depolarizer molded under.the critical pressure giving minimum internal'resistance beni andcontaining a small proportion of a weak organic acid.

6. A dry cell of the Leclanch type having its depolarizer molder underthe critical pressure giving minimum internal resistance lowingrequirements:-(a) having little or no action on manganese dioxid; (b)little or no action on zinc; (c) its ammonia and zinc salts must befreely soluble in the battery solution; said depolarizer being subjectedto a pressure in the region of the critical pressure giving an internalresistance to thecell about a minimum value. i

8. A depolarizer for an electric cell con-v sisting of a mixturecontaining manganese dioxid, carbon and a body fulfilling the followingrequirements :-(a) havinglittle or no Iaction on manganese dioxid; (b)little or no action on zinc; (),'its ammonia and y zinc salts must befreely soluble in the battery solution; said depolarizer being subjected to a pressure in the region of the critical pressure giving aninternal resistance to the cell about va minimum value, together withmeans for maintaining the aforesaid resistance at about the minimumvalue.

9. A /depolarizer for an electric cell con- In testimony whereof I havevsigned m name to this specification. i

GEORGE NIKOLAYEVIGH N'IONOFF.

